METHYLMALONIC ACIDEMIA A Disorder Associated with Acidosis, Hyperglycinemia, and Hyperlactatemia

Abstract

SummaryThe clinical and biochemical features of a case of methylmalonic acidemia, a newly described inborn error of metabolism, are reported.The cardinal feature was chronic metabolic acidosis which was controlled by restriction of the protein intake. Periodically, exacerbations with vomiting, dehydration, lethargy, coma, and even peripheral circulatory failure have appeared. The crisis have been induced by trivial acute infections and by overloading with protein. Mild symptoms appeared in the neonatal period, crises after an age of 4 months. When the protein intake was high, there was marked muscular hypotonia, developmental retardation, and neutropenia. When acidosis was controlled by protein restriction and treatment with bicarbonate the baby made marked progress. At 23/12 years of age the development was normal.The patient excreted large amounts of methylmalonic acid in the urine and the blood level was elevated. Other biochemical abnormalities were hyperglycinemia, hyperglycinuria, and hyperlactatemia.The hypothesis that the basic metabolic defect in methylmalonic acidemia and the ketotic type of hyperglycinemia is the same is discussed, as are the similarities between methylmalonic acidemia and infantile lactic acidosis.